Effects of prenatal multimicronutrient supplements on birth weight and perinatal mortality:: a randomised, controlled trial in Guinea-Bissau

Objectives: To assess the effects of daily prenatal multimicronutrient supplementation on birth weight (BW) and perinatal mortality. Design: Randomised, controlled, double masked trial. Setting: Urban Guinea-Bissau, West Africa. Subjects: A total of 2100 pregnant women ( 2277 weeks pregnant at entry) were recruited through antenatal clinics, of which 1670 (79.5%) completed the trial. BW was available for 1100 live born babies. Interventions: Identical-looking supplements containing one (MN-1) or two (MN-2) Recommended Dietary Allowances (RDA) of 15 micronutrients, or iron and folic acid ( control). Results: Mean BW among 1100 live born infants was 3050 +/- 498 g with 11.9% being low birth weight ( LBW, BW <2500 g). Perinatal mortality was 82 per 1000 deliveries (N = 1670), and neonatal mortality 45 per 1000 live births ( N = 1599). Mean BW in MN-1 ( n = 360) and MN-2 ( n = 374) groups were 53 [-19; 125] and 95 [24; 166] g higher than controls (n = 366). Proportion of LBW was 13.6% in control, and 12.0 and 10.1% in the MN-1 and MN-2 groups, respectively ( P = 0.33). Among anaemic women (30%), MN-2 increased BW with 218 [ 81; 354] g compared to controls, with a decreased risk of LBW of 69 [ 27; 87]%. There were apparently no differences in perinatal mortality between groups. Conclusions: Prenatal micronutrient supplementation increased BW but did not reduce perinatal mortality in this study. Multimicronutrient supplementation with two RDA should be considered in future programmes to reduce the proportion of LBW.